The present invention relates to a multilayer flake or film that comprises a chiral (cholesteric) liquid crystal polymer that can be used for coding (also named coding flakes) for purposes such as tracking and tracing items as well as for authentication purposes such an anti-counterfeiting measure.
U.S. Pat. No. 6,200,628, which is incorporated by reference herein in its entirety, relates to the use of particles formed of at least two thin inorganic layers, distinct in their chemical composition, in a predefined analytically identifiable sequence and/or predefined analytically identifiable thickness, for the marking of coating compositions and/or for the encoding of bulk materials and products formed thereof. Such encoded particles are used as tags and as security elements thus preventing the article from being counterfeited.
US 2011/0258924 A1 and WO 2009/139631 A1, which are incorporated by reference herein in their entireties, disclose product marking and identification, more in particular to methods of differentiating products or product versions and to methods of product authentication including marker systems for product authentication, a kit of parts for applying a marker system to a product and identifying the marked product, such as seeds.
US 2011/0101088 A1 and WO 2010/115879 A2, which are incorporated by reference herein in their entireties, disclose markings for the secure tracking or tracing of an item or article, comprising a polymeric liquid crystal material having determined optical characteristics, which allow for its authentication and reading by a machine, as well as its authentication by the human eye. The marking can be produced on a substrate by a variable information printing process in the form of indicia representing a unique code, which allows for its identification. The marking is further preferably laid out such that part of it is invisible to the unaided human eye.
U.S. Pat. No. 7,702,108 and US 2003/136837 A1, which are incorporated by reference herein in their entireties, disclose method and equipment for the authentication of items, in particular security documents, at advanced security levels with the help of state-of-the-art technical communication means.
US 2010/0178508 A1, which is incorporated by reference herein in its entirety, discloses a multilayer of cholesteric liquid crystal polymer, wherein at least two layers of cholesteric liquid crystal polymer differing in at least one optical property are arranged on top of each other, characterized in that said at least two layers are chemically inter-layer cross-linked through the polymer network, such as to form a mechanically unique solid body which can be comminuted to pigment without deterioration of its inner structure and which has an abrupt change of cholesteric liquid crystal pitch at the interface between said at least two layers of cholesteric liquid crystal polymer.
US 2011/0101088 A1, which is incorporated by reference herein in its entirety, discloses that “Track & Trace” applications, such as including at least one security element, able to certify the authenticity of the marked good as an original one.
WO 2010/115879 A2 and its U.S. National Stage application Ser. No. 13/262,348, which are incorporated by reference herein in their entireties, disclose a marking of polymeric liquid crystal material having determined optical characteristics allowing its authentication and reading by a machine and its authentication by the human eye. The marking can be applied onto an item, good or article by a variable information printing process. The marking can be in the form of indicia representing a unique code which allows for an easy authentication by the human eye and a secure tracking and tracing of the marked item, good or article throughout its life cycle.
US 2010/0200649 A1, which is incorporated by reference herein in its entirety, relates to a distinguishable marking through its polarization effect that can be used in all kind of authentication, identification, tracking and tracing applications, for all kind of documents or goods. As disclosed therein, there are many methods, markings, authentication equipment and systems disclosed in the prior art which all make use of a random particle distribution as an identification means for documents or items. US 2010/0200649 A1 discloses that ideally, a deliberately introduced random characteristic, embodied by a marking having a random distribution of particles, and the corresponding authentication means should comply with the following requirements: a) no mechanical contact between the document or item and the reading device; b) sufficiently large detection area, to allow for easy localization and focusing; c) strong signal response of the marking; d) compatibility with a large variety of application techniques; e) small size of generated positional information data records; f) particles easy to find; g) capable of high operation speed; h) high durability/stability of the marking. Flakes disclosed in US 2010/0200649 A1 permit the generation of unique codes based upon a random distribution of the flakes. However, it would be advantageous to include further security elements in the films or flakes to permit an even more efficient level of coding.
Moreover, it would be useful to provide in addition to coding more efficient track and trace applications which allow for the identification of an individual item, with at least one security element, which additionally allows for the authentication of the item as being genuine. It is especially useful to be able to track items, such as pharmaceuticals, cosmetics, etc., when an item or items are travelling along a supply chain from producers to retailers.
Moreover it would be also useful to quickly and reliably retrieve an item or a group of items having a unique code in a database which contains billions of code generated from one or more signatures present in said item or group of items to ascertain and/or verify the location along a supply chain or at the retailers or producers of one or more items and/or ascertain whether or not one or more items is genuine or counterfeit.